The class of athletic training devices arranged to be mounted upon or connected to a hand held device for striking a ball in the course of a game, such as a bat used in baseball or a racket used in tennis, includes several prior art patents, as follows:
First, Mogren U.S. Pat. No. 2,134,451 disclosing an exercising device including a suspended weight connected to a cooperating hand held bat or tennis racket connected yieldably to the suspended weight by a flexible member or cable passed over a supporting pulley;
Second, Peterson U.S. Pat. No. 3,913,911 disclosing the combination of a tennis racket and selectively detachable weights mounted on opposite outside edges of the head of a tennis racket for use in play and providing modified weight and balance of a tennis racket so equipped;
Third, Moreland U.S. Pat. No. 3,907,292 disclosing a tennis racket provided with a curved hollow tube attached symmetrically to the outer edge of the frame of the head portion thereof enclosing two sets of weights respectively coacting with a pair of opposed spring members, in order to combine the properties of a "light" and a "heavy" racket in a single racket by shifting the weights longitudinally of the racket in response to the application of centrifugal force thereto as the racket is swung by a player. This configuration of spring resisted weights is so arranged and functions in such a manner as to be compatible with the employment of a racket so equipped either for exercise or in play;
Fourth, Latham et al U.S. Pat. No. 3,625,512 disclosing a racket including a frame made from an aluminum extrusion of a particular cross-section especially well suited to its use in a racket, also including provisions for mounting and enclosing weights selectively added to and fixedly secured to the outer surface of the extruded frame forming the peripheral portion of the head of a tennis racket; and
Fifth, Ross U.S. Pat. No. 3,874,666 disclosing an accessory device for attachment to a racket, comprising a pair of opposing elements interconnected through and clamped in engagement with the opposite surfaces of the interwoven strings traversing the head portion of a racket. While the manner of mounting this accessory device upon the head portion of a racket generally resembles the manner of attaching the exercise weight assembly disclosed herein to a tennis or other racket, its surface its shape, its shown location on the head portion of a racket, and its purpose are all profoundly different from the purpose of the exercise weight assembly of the present invention.
The first four patents preferred to above share in common an express reference in each to a suitable provision, consistent with the particular structure described and illustrated in each, for selectively adjusting the amount of weight operative to constrain the movement of a tennis or other racket as it is swung by a player either in exercise or in play.